1. Technical Field of the Invention
The present invention relates to the field of electronics, and more particularly to device and method to detect parked vehicles at night.
2. Prior Art
Locating a vacant parking space causes much frustration to motorists. It increases fuel consumption and has a negative impact to the environment. To conserve energy resources and enhance the quality of the environment, it is highly desired to develop a parking-monitoring system, which can transmit substantially real-time parking states (i.e. occupied or vacant) to motorists. Based on the parking states, a motorist can be guided towards a vacant parking space at destination.
Parking enforcement is an important aspect of city management. The current parking-enforcement system is patrol-based, i.e. parking enforcement officers patrol the streets and/or parking lots to enforce the parking regulations. This operation requires significant amount of man-power and also consumes a lot of fuel. It is highly desired to take advantage of the above-mentioned parking-monitoring system and automatically measure the parking time for each monitored parking space.
Both parking monitoring and enforcement are based on parked vehicle detection. Parked vehicle detection preferably can be carried out both during the day and at night. This is particularly important for commercial districts during the day and for residential areas at night. Relying on the natural light to capture the images of a parking area, prior art devices only work during the day. At night, because street lights generally do not provide adequate lighting coverage (often blocked by trees or other obstacles), prior art devices cannot reliably detect parked vehicles.